1. Field of the Invention
The present invention relates to a method of improving residue and thermal characteristics of a semiconductor device, and more particularly to a method of improving residue and thermal characteristics of a semiconductor device, which forms a silicide by adding a capping layer of titanium nitride (TiN) on the existing triple layers of Si, Co and Ni, thereby solving a problem of residue remaining thereon and ensuring an enhanced thermal stability when manufacturing the semiconductor device.
2. Description of the Related Art
A continuing trend in current logic technology of 0.13 μm or less is to replace cobalt silicide with nickel silicide for enhancing a short channel effect. Nickel silicide applications are expanding to a nano-CMOS (Complementary Metal Oxide Semiconductor) due to its advantages in that nickel silicide can have a constant sheet resistance according to a line-width even in a fine line-width less than 0.10 μm as well as a low silicone consumption rate and a low specific resistance.
However, compared with cobalt silicide, since nickel silicide exhibits unstable thermal characteristics, such as phase transformation toward NiSi2 or easy occurrence of cohesion, during an interlayer dielectric film deposition process, a contact heat process and the like, which are subsequent processes carried out after forming the silicide, it is required to settle these problems without delay.
Thus, in order to solve the problems, a conventional method forms a silicide layer through a heat treatment process after depositing double layers of cobalt/nickel (Co/Ni) or nickel/cobalt (Ni/Co) on a silicone substrate having a transistor formed thereon.
However, in the conventional method for providing the thermal stability using the double layers of cobalt/nickel or nickel/cobalt, a compound consisting of Si, Co and Ni is formed by a reaction of these elements and the compound exhibits a strong resistance against an etching liquid, so that a residue remaining after formation of the silicide continues to remain on a side wall and a field after an etching process, causing a problem in that a bridge can be easily formed.
FIG. 1 is a diagram illustrating the problem caused by the residue remaining without being removed when the double layers of cobalt/nickel or nickel/cobalt are used in the conventional method without a capping layer.
That is, according to the conventional method, even though a wet etching process is applied in order to remove the residue remaining after forming the silicide, the residue still remains without being completely removed.